CODEWITHSUNDEEP
debuggingloggingcrashgdb
kp11
kp11

Reputation: 2125

Help for gdb debug crash logging

I have been debugging in GDB (C code). The issue is if I run my application and if it crashes, the control comes back to main()(app restarts). Hence will have no idea where it crashed. So I spend a lot of time stepping through each function.

I would like to know if there is anyway a log can be enabled which will generate the last line of execution before crash. This is just my assumption, if there is any other simpler way of doing this please let me know, this would save a great deal of time for me!

Also if the gdb generates a log where would the path be?

Thanks in advance.

Upvotes: 3

Views: 19059

Answers (2)

akD
akD

Reputation: 1257

Run your program in gdb mode.

 $ gdb ./myProgram


Set break point to expected location.

 $ break functionName


Or set break point to particular line number.

 $ break 15


Start the execution

 $ r


Step into or step out the execution by 's' or 'n'

 $ s


once the program crash, do 'bt' for backtrace.

 $ bt


you can go up and down in your trace by 'up' & 'down' command

 $ up


Can also take alternate way. Debug program with “core” as the core dump file.

 $ gdb executableFilename core
 $ bt

Upvotes: 3

Jason Orendorff
Jason Orendorff

Reputation: 45086

This question is a little unclear to me, but I'll take a stab:

If you have GDB attached to the crashing process when it crashes, a crash should stop the program and put you back at the (gdb) prompt. If you then type bt, you should see the stack.

If you do NOT have GDB attached, then this answer to a related question might help. (In short, maybe you want the system to create a core dump when the program crashes. A core dump is just a file that contains a lot of information about the crashed process. You can use GDB with the core dump to see the stack.)

If you don't know, post what you see on the screen when this happens, and we'll guess.

In any case, the program definitely should not start over at main(). It seems worthwhile to track down why this happens and precisely what's going on. Does control really jump to main in the same process, as opposed to another process somehow being automatically started?

Upvotes: 4

Related Questions